Electromagnetically-actuated switch



Nov. 20, 1928. 4 1,691,920

G. H. CHAPMAN ELECTROMAGNETICALLY ACTUATED SWITCH Filed May 5, 1921 JIQ] Patented Nov. 20, 1928.

"UNITED STATES GEORGE H. CHAPMAN, OF CHICAGO, ILLINOIS.

ELECTROMAGNETICALLY-ACTUATED SWITCH.

. Application filed May 5,

y This invention relatesto devices for" actuating electric switches in pipe organs and other musical instruments employing such switches. In its chief intended, application I it is employed to actuate what is known as a coupler switch or combination switch in a pipe organ. i p

Heretofore as far as I am aware pivoted or rocking switches of this character have been held in one position by spring means, and operated by means of pneumatic mo tors. One object of my present invention is to improve the operating mechanism of this type of switch by substituting for the usual pneumatic motor, an electric motor which takes the form of a magnet, and preferably a magnet of the solenoid type. r

7 Other more specific objects of the invention are, to provide an improved device for re ulating the distance of travel of the movable core or plunger of the magnet, to prevent both the plunger and the spool of the magnetfrom turning on their own axes, and to provide an improved means for regulating the length of the connection between the plunger of the magnet and the actuating arm of the switch. t

Other objects and advantages of the invention will be apparent to those skilled in the art as the same becomes better understood by reference to the accompanying drawings, wherein I have illustrated one practical and approved embodiment of the invention, and in ;which I 1 is a top plan view;

Fig. 2 is a vertical section through the magnet and its support with the switch shown in end elevation;

Fig; 3 is a'sectional detail enlarged on the line 3-3 of Fig. 1, showing the switch supporting bracket and the switch actuating spring;

Fig. 4 is a perspective view of the switch sup orting bracket, viewed in the direction indicated by the arrow A in Fig. 1.

' Referring to the drawing, 5 designates as an entirety a rectangular frame which may represent a portion of a switch board of a pipe organ, on one side of which is pivoted ahorizontal wooden switch-bar 6 of a well-known type, said switch-bar carrying a group of wire contacts 7 that. are simultaneously moved into and out of contact with metal strips 8 mounted in one face of theboard 5; the electric circuits closed through these contacts operating to draw'the stops of pipes 1921. Serial No. 466 885. I

which are in octave or other relation to the other pipes of the organ; to operate percussion instruments; to draw combinations, and perform other functions, The switch-bar. 6 carrying the group of contact. members 7 is pivoted at its end by screw pintles 9 in a pair of supporting brackets designated as a whole by lO and bestshown in perspective elevation in Fig. 4. These switch supporting brackets are preferably made as die-castings, and, to effect economy of manufacture, the two brackets at the opposite ends of the switch are made identical in structure so as to be interchangeable by simply inverting them. 11 designates the base or attachment plate of the bracket, which is a flat member formed with holes to receive suitable fastening screws 13 bywhich they are secured to the face of the board 5. 14 is the arm of the bracketprojecting at. right angles to the base 11 fromone edge ofthe latter, and having formed therein upper and lower holes 15, corresponding holes of each bracket forming the bearing for the switch pintle 9. The arm of the bracket is further formed with a pair of upper and lower holes l6, corresponding holes of'each bracket forming an anchorage for one end ofa coil spring 17, which, as clearly shown in'Fig. 3 is coiled one or more times around the pintle 9, and has a tangential projecting end portion 17 that bears upon a pin or stud 18 set in the end of the switch-bar 6. This type of spring is superior to the grasshopper spring heretofore used directly beneath the switch arm. It is on the front of the board and very accessible for purposes of adjustment or re placement. It does not project beyond any face of the switch-bar and hence is not liable to get caught and damaged; and it is easily accessible as compared with springslocated on the rear of the board which isdiliicult of access. It will be observed that by reason of the above described construction of switch supporting bracket, it can be used at either end of the switch by a mere inversion, thereby dispensing with the necessity of providing rights and lefts.

On the other side of the frame 5 is mounted by screws 19 and 20 a wide U-shaped metal frame 21, one limb 21 of which is preferably made separable as shown, and attached to the vertical member of the frame by screws 22 for convenience in assembling of the parts carried within the frame. Within this frame is mounted a solenoid spool 23 whichhas its heads 2% non-rotatably secured to the upper and lower limbs of the frame by dowel pins 25. Mounted within the lower end of the spool 23 is an iron plug 26 formed with a concave or V-shaped upper end 26", and above the plug 26 is the movable core or plunger 27 of the magnet which has a pointed or V- shaped lower end 27 matching the concave upper end 26 of the plug 26. To vent the space between the lower end of the plunger 27 and the upper end of the plug 26, the latter is formed with a longitudinal groove or vent channel 28, and the lower end of the plug is chamtered as shown at 29, this cham fer lying above vent hole 30 in the lower horizontal limb of the frame 21; The plug 26 is secured to the frame and within the spool by a screw 31, as clearly shown in Fig. 2.

The upper end ott'the plunger 27 is tapped to receive an eye-screw 32, and this latter is connected by a threaded link to an arm 34: on the switch bar 6, said arm. extending through a vertical slot 35 in the board 5. The arm 3%. is apertured to receive the threaded link 33 and is operatively connected to the latter by upper and lower nuts 36 and 3? and interposed washers 88. The length oi? this connection can be nicely adjusted by effecting a rough regulation through the eye-screw 32 and a fine regulation by the nuts 36 and 37, if necessary. Mounted on the upper end of the plunger 27 is a horizontally projecting arm or plate 39 swedged on the plunger; a lock nut 40 on the eye-screw 32 preventing the latter from turning. The outer end of the arm 39 has a slot or hole 41 by which the arm is slidably engaged with a post 42 set in the upper horizontal frame member 21. lhe post 42 is threaded and carries a nut 43 and washer ll forming a cushion stop to limit the rising movement of the plunger, and the eX-' tent. of this movement can be regulated by screwing the nut 43 up or down on the post 42. The purpose of this last described feature is to hold the plunger against turning on its own axis. which, with the described connections to the switch arm, might result in accidental lengthening or shorteningof such connections which mightcause the switch to fail to function properly.

I have found in practice that anelectromagnetis more durable, economical of space and otherwise desirable in many cases as an actuating device for switches of this type. than the pneumatics heretofore used for this purpose since it allows the key-disk to be more compactly built; and a solenoid magnet of the special type herein shown and described is especially useful and advantageous for this purpose, since the described conical formation of the lower end of the plunger and the upper end of the plug creates a smaller separation, or air gap, between the two, for a given extent or plunger movement, than exists where the two ends are square. It is also noiseless, has a long range of pull, and requires no regulation.

It is believed that the novel structural features of my invention and the mechanical advantages fiowing therefrom will be readily understood by persons familiar with this art without further detailed description. Manit'estly, the structural details may be considerably varied from those shown and described without altering the substantial character of the invention or sacrificing any of the advantages thereof; hence I reserve all such variations and modifications as fall within the spirit and purview of the appended claims.

I claim:

1. In a switch-actuating mechanism for musical instruments, the combination of a vertical switch board carrying a horizontal row of lixed contacts and having a vertical slot therein, brackets mounted on one side of said switch board on opposite sides respectively of suit slot, a horizontal switch bar carrying end pintles journaled in said brackets, said switch bar carrying contacts adapted to co-operate with the contacts of said switch board, an arm on said switch bar extending through the slot of said switch board, a solenoid magnet mounted on the opposite side of said switch board below the slot of the latter, a, lengthwise adjustable and flexible connection between the plunger of said magnet and the free end of said arm, means for preventing turning movement of the plunger of said magnet, and springs anchored to said brackets and tending to rock said switch bar in a direction to separate said contacts.

2. In a switchactuating mechanism for musical instruments, the combination of a pivoted switch bar, a laterally projecting apertured arm thereon, a solenoid magnet including an endwise movable plunger, an eye screw mounted in the outer end of said plunger, a screw-threaded pull rod articulated at one end to said eye screw and extending through the aperture of said arm. nuts on said pull rod above and below said arm whereby the efi'ective length of said pull rod may be adjusted, and means to prevent turning movement of said plunger.

enonen H. CHAPMAN. 

